GoalTracker: Comparing Self-Monitoring Strategies for Weight Loss

This study will examine whether a digital health intervention (GoalTracker) can promote weight loss among adults who are overweight or obese. Engagement in self-monitoring often declines over time, which is then associated with suboptimal weight loss. Finding ways to improve self-monitoring engagement, particularly in the first month of treatment, is needed. Promoting mastery, self-efficacy, and self-regulatory skills may help with maintaining high engagement. The investigators aim to enroll 105 participants. All groups are asked to self-monitor daily on their smartphone using the free commercial mobile application MyFitnessPal over the course of the 12-week intervention. Specifically, the study aims to... 1. Determine the effect of a Sequential self-monitoring intervention, compared to a Simultaneous self-monitoring intervention on weight change, caloric intake change, and proportion of individuals achieving 5% weight loss. 2. Determine the effect of the Sequential self-monitoring intervention, compared to the Control, on the same variables. 3. Compare self-monitoring engagement by intervention arm. 4. Examine the relation between self-monitoring engagement and weight loss. 5. Investigate theoretical mediators (self-efficacy, mastery, and self-regulation) on the relation between treatment arm and weight change.